One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,11)(8,12)(9,10)(15,23)(16,19)(20,25)(24,26) involution — undirected(6,10)(11,12)(13,14,17,22)(15,24,23,26)(16,25,19,20)(18,28,27,21)(2,4)(13,15,17,23)(14,19,22,16)(18,20,27,25)(21,26,28,24)(5,7,9,8)(6,11,10,12)(13,16,17,19)(14,20,22,25)(15,21,23,28)(18,24,27,26)(5,8,9,7)(6,12,10,11)(14,21)(16,24)(18,27)(19,26)(20,25)(22,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.